﻿using System.Data;
using System.IO;

public static class CsvHelper
{
    /// <summary>
    /// 导出报表为Csv
    /// </summary>
    /// <param name="dt">DataTable</param>
    /// <param name="strFilePath">物理路径</param>
    /// <param name="tableheader">表头</param>
    /// <param name="columname">字段标题,逗号分隔</param>
    public static bool dt2csv(DataTable dt, string strFilePath, string tableheader, string columname)
    {
        try
        {
            string strBufferLine = "";
            StreamWriter strmWriterObj = new StreamWriter(strFilePath,false,System.Text.Encoding.UTF8);
            strmWriterObj.WriteLine(tableheader);
            strmWriterObj.WriteLine(columname);
            for (int i = 0; i < dt.Rows.Count; i++)
            {
                strBufferLine = "";
                for (int j = 0; j < dt.Columns.Count; j++)
                {
                    if (j > 0)
                        strBufferLine += ",";
                    strBufferLine += dt.Rows[i][j].ToString();
                }
                strmWriterObj.WriteLine(strBufferLine);
            }
            strmWriterObj.Close();
            return true;
        }
        catch
        {
            return false;
        }
    }

    /// <summary>
    /// 将Csv读入DataTable
    /// </summary>
    /// <param name="filePath">csv文件路径</param>
    /// <param name="n">表示第n行是字段title,第n+1行是记录开始</param>
    public static DataTable csv2dt(string filePath, int n, DataTable dt)
    {
        StreamReader reader = new StreamReader(filePath, System.Text.Encoding.UTF8, false);
        int i = 0, m = 0;
        reader.Peek();
        while (reader.Peek() > 0)
        {
            m = m + 1;
            string str = reader.ReadLine();
            if (m >= n + 1)
            {
                string[] split = str.Split(',');

                System.Data.DataRow dr = dt.NewRow();
                for (i = 0; i < split.Length; i++)
                {
                    dr[i] = split[i];
                }
                dt.Rows.Add(dr);
            }
        }
        return dt;
    }
}

